A guideline published in January on brain scans for beta-amyloid plaques has been updated to address concerns raised by a key government advisory committee.

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A guideline published in January on brain scans for beta-amyloid plaques has been updated to address concerns raised by a key government advisory committee.

Note that the guidelines recommend that amyloid brain scans should be used only in patients with progressive or unexplained mild cognitive impairment, those with tentative diagnoses of "possible" Alzheimer's disease with features unusual for the illness, and patients younger than 65 with progressive dementia.

A guideline published in January on brain scans for beta-amyloid plaques has been updated to address concerns raised by a key government advisory committee.

Among other recommendations, it said that amyloid brain scans should be used only in patients with progressive or unexplained mild cognitive impairment, those with tentative diagnoses of "possible" Alzheimer's disease with features unusual for the illness, and patients younger than 65 with progressive dementia. These would reflect the cases in which such scans would most likely be informative for patient management, the authors indicated.

The guideline also recommended that a "dementia expert" -- a physician with training and/or experience in managing patients with Alzheimer's disease and other dementias -- be consulted before ordering scans and in interpreting the results.

Dean Hartley, PhD, director of science initiatives at the Alzheimer's Association and an author of both the original guideline and the new update, told MedPage Today that the guideline committee wanted, in part, to address concerns raised by the Medicare Evidence Development and Coverage Advisory Committee (MEDCAC) at a meeting shortly after the guideline came out.

The panel voted against recommending Medicare coverage of the scans. Members' reservations included uncertainty about what exactly defines a "dementia expert," which is not a recognized medical subspecialty. The panel also questioned whether clinicians would order the scans more broadly than recommended either in the guideline or in florbetapir's label, and whether most radiologists were qualified to interpret the scans.

The update explained that, in the committee's thinking, a dementia expert "should be self-identified as a physician trained and board-certified in neurology, psychiatry, or geriatric medicine who devotes a substantial proportion (≥25%) of patient contact time to the evaluation and care of adults with acquired cognitive impairment or dementia, including probable or suspected Alzheimer disease, as confirmed by peer recognition."

It added that such a physician would "likely" have board certification or fellowship training in geriatric psychiatry or neurology or behavioral neurology or psychiatry.

In response to MEDCAC members' concerns that such experts are rare, the committee opined that their numbers would grow commensurately with "demand for amyloid PET referral." Eventually, Hartley and colleagues wrote, the need for such experts may diminish as more clinicians and radiologists gain experience with the scans.

The guideline update also expanded on the original document's discussion of etiologic uncertainty in cases of mild cognitive impairment. In particular, the authors cited the situation of patients who may show dementia symptoms along with vascular pathology as well as other "potentially confounding circumstances" such as depression, drug side effects, substance abuse, and other medical conditions with psychiatric complications.

"In these relatively unusual but important cases, substantial uncertainty then remains as to the cause of the syndrome, and further patient care is severely constrained or compromised," Hartley and colleagues wrote, suggesting that amyloid scans can help resolve the uncertainty.

"Once the cause of deficits is properly assessed, a more confident diagnosis frequently helps anticipate future needs, including closer monitoring for progression and safety, periodic functional assessments for retirement planning, and allocation of financial and family resources," the update said.

Finally, both the Alzheimer's Association and the SNMMI committed to developing educational materials to promote use of amyloid scans only within the label indications. The latter group in particular is putting together a maintenance-of-certification module for this purpose.

Hartley told MedPage Today that the guideline would be treated as a "living document" with frequent updates as warranted by advances in knowledge about amyloid pathology and scanning technology.

The work had no commercial funding.

Authors declared they had no relevant financial interests.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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